Many types of prior art container lids have been devised for closing pails or containers. These container lids are generally applied to an open ended pail or container which has a curled annular rim formed about an open end. Prior art lids are generally disc-shaped and have a downwardly facing annular groove or channel adapted to receive the annular rim of the container. A series of lid lugs project downwardly from the annular channel of the lid for attaching the lid to the container rim. For example, lug lids for use with two and one half to seven gallon containers generally contain an even number of lugs on the order of 16 to 20 lugs, which are formed along a circumferential edge of the lid with spaces formed between the lugs. The lid is sealed to the container by use of a crimping tool to crimp the lugs about the annular rim of the container in a sealing arrangement.
These metal container lids are generally manufactured by blanking or punching a rectangular or square sheet of metal with a pattern comprising a plurality of unfolded container lids or blanks. For example, a typical prior art punch pattern is shown in FIG. 1, and comprises four closely spaced unfolded container lids which are symmetrical in shape. One major disadvantage of the prior art container lid design and punch pattern is that costly material is wasted in between the holes (i.e., the scrap skeleton) even though the blanks are closely spaced together. In addition, a larger sheet of material is required than necessary in order to produce a given number of container lids. This waste is a function of the container lid design and the amount of spacing allotted for adjacent blanks. Scrap material represents an expensive loss which is only partly recoverable and which requires additional resources to convert into a usable form. Another disadvantage of the prior art is that more time is wasted in gathering and transporting the scrap to recycling centers. Yet another disadvantage of the prior art is that paint used to coat the sheet prior to punching is wasted as well as the additional energy required to cure the paint on a larger sheet.
It is therefore desirable to provide an improved container lid design and blank pattern layout which reduces the amount of scrap material generated and thus results in considerable cost savings with very few drawbacks. It is further desirable to provide an improved container lid design and blank pattern layout which reduces the sheet size of the material while producing an equivalent number of lids.